Abstract
Purpose: :
To study pancreatic islets transplantation in the context of VEGF- pretreatment to prevent diabetic retinopathy in SD rats.
Methods: :
Methods: The current research project was conducted in compliance with the ARVO Statement for the Use of Animals in Ophthalmic and Vision Research. In this study, diabetic rat model was made by intraperitoneal injection of Streptozotocin (STZ). One week after the injection, islets from donor rats were isolated with collagenase and transplanted under the kidney capsule with different treatment. Receiver rats were divided into three groups depending on the islets treatment. Group V received VEGF pre-cultured islets transplant; group M received islets transplant through media-pretreated islets; and group C received islets without pre-culture. Blood glucose and body weight were monitored daily after the transplant. At the end of study, the transplanted islets were retrieved for immunohistochemistry study; and eyes were enucleated for diabetic retinopathy evaluation.
Results: :
Results: Blood glucose was very well controlled through the whole study course with stable body weight in group V rats. Animals in group M showed short period of normal blood glucose and body weight maintenance; while the group C animals only had initial two days of normal blood glucose and experienced body weight loss through the whole time course of the study. In terms of diabetic retinopathy, 13% of animals in group M developed mild NPDR, 54% with moderate NPDR, 17% with severe NPDR and PDR. In group C receivers, 8% developed mild NPDR, 58% developed moderate NPDR, 8% developed severe NPDR, and 25% developed PDR. In group V, however, only one animal (4%) developed mild NPDR and no moderate or severe NPDR or PDR development during the whole study period.
Conclusions: :
Conclusions: From this study, we concluded that rats received VEGF-pretreated islets could maintain normal blood glucose level, normal body weight and no serious diabetic retinopathy. It indicated that the VEGF promoted blood vessels regeneration in the islets grafts but did not cause worsening diabetic retinopathy due to its indirect euglycemia effect by maintaining islets grafts re-vascularization. This result supported the previous study that the VEGF worsened diabetic retinopathy through neovascularization was secondary to the long-term effect of hyperglycemia in diabetes patients.
Keywords: diabetic retinopathy • microscopy: light/fluorescence/immunohistochemistry • imaging/image analysis: non-clinical